https://naiwaen.debuggingsoft.com/2021/02/rhel8-x-%e0%b9%81%e0%b8%81%e0%b9%89%e0%b8%9b%e0%b8%b1%e0%b8%8d%e0%b8%ab%e0%b8%b2-ssh-sftp-%e0%b8%9e%e0%b8%9a-sign_and_send_pubkey-no-mutual-signature-supported/